1. Field of the Invention
This invention relates to a rear suspension system for motor vehicles and more particularly to a rear suspension system for off-road motorcycles, including three-wheeled motor vehicles having a single front wheel and two rear wheels and four-wheeled motor vehicles called buggies.
2. Description of Relevant Art
Off-road motorcycles there have used relatively large-sized and extremely low-pressure tires in consideration of comfort and stability. Road shocks are first cushioned by the tires and then further cushioned by suspension systems for wheels and particularly by a suspension system for rear wheels.
For such a rear suspension system to experience large bounces of the rear wheels and obtain good cushioning characteristics, it is preferable that the rear wheels be supported by a swing arm mechanism and that a progressive link mechanism be disposed between the swing arm mechanism and a damper. But in the case of the above-mentioned vehicles, it is necessary to relatively lower the vehicular height in order to lower the center of gravity of the vehicle body and to dispose an engine and its associated devices under the main frame and chassis. Therefore, if a conventional damper with a long stroke is to be mounted between a swing arm mechanism which supports rear wheels and an upper vehicular body frame, insufficient room may be available for its full stroke. It may be impossible to fully utilize this characteristic of the damper because of insufficient height and space even if its mounting can be done without any trouble. The above and like problems are encountered in the above-mentioned type of vehicles.
The present invention effectively overcomes such problems of a rear suspension system in vehicles having at least one rear wheel and improves its cushioning characteristic.